The present invention lies in the field of protecting electronic components.
More particularly, it relates to an electronic component suitable for detecting an active attack.
It is common practice to distinguish active attacks from passive attacks.
A passive attack is an attack in which the attacker is content merely to observe the activity of the component.
In contrast, an active attack is an attack by injecting a fault whereby the attacker physically disturbs the component while it is executing sensitive algorithms or commands.
Such disturbances are manifested at the component by a delivery of energy (e.g. light or electromagnetic energy). This delivery of energy gives rise to an increase in current that serves to place the component in an unexpected and fragile state.
It is known to evaluate the security of smart cards by analyzing their behavior in response to injecting a fault by means of light energy from a laser.
FIG. 1 shows the principle of such an evaluation.
With reference to FIG. 1, a component 10 is connected in series between two resistors having resistances R, one connected to ground and the other to a positive voltage Vcc, and then the component is illuminated with a laser pulse.
This delivery of energy gives rise to surplus current both upstream (Vcc) and downstream (Gnd) of the component at the moment of the light disturbance and throughout the duration thereof. This surplus current may be caused by two reasons:                it may be induced by the light pulse, with the light creating as many holes as electrons; the holes flow towards the positive voltage Vcc and the electrons to ground, thereby impacting the currents i1 and i2;        it may also be caused by short-circuit currents in the component that are themselves caused by the light pulse.        
At present, no method is known for detecting such attacks.
Document EP 1 804 199 describes a method of detecting an attack that consists in varying the positive voltage Vcc. Unfortunately, that method does not serve to detect an attack by delivering energy, of the same type as the above-described laser attack, which attack has no effect on the voltage Vcc.